Dyeable linear polyesters modified by a metallosulfophenoxy-substituted benzoic acid or ester



United States Patent 3,164,567 DYEABLE LINEAR POLYESTERS MODFFIED BY AMETALLOSULFOPHENGXY SUBSTITUTED BENZUIC ACID 0R ESTER Christian F. Horn,South Charleston, W. Va, assignor to Union Carbide Corporation, acorporation of New York N0 Drawing. Filed Nov. 1, 1961, Ser. No. 149,22713 Claims. (Cl. 26049) This invention relates to new condensationpolymers.- The invention also relates to textile articles, i.e., fibers,filaments, yarns, etc., as Well as to films and other structures of saidpolymers which have an improved affinity for dyestuffs.

Synthetic linear polyesters are well known to the art and are readilyprepared,-for example, by the reaction of dibasic carboxylic acids, ortheir ester-forming derivatives, with dihydric alcohols, or theirfunctional derivatives. The high-molecular Weight linear polyesters thusobtained find frequent use in the production of textile articles, films,and the like. Of particular interest in this regard are the polyestersof terephthalic acid and its esters with glycols, such as polyethyleneterephthalate, and the polyester from dimethyl terephthalate and1,4-cyclohexanedimethanol, etc. Unfortunately, the filamentous productsproduced from these polyesters have little afiinity for dye'stufis byconventional dyeing procedures, and consequently, their utility in thefabric field is somewhat restricted.

It was to be expected that many efforts would be made to improve thedyeability of a filmand filament-forming material having as manydesirable characteristics as those possessed by polyethyleneterephthalate. Such efforts have indeed been made. However, the effortsthat have resulted in some degree of success in making polyethyleneterephthalate more dyeable have done so only at the expense of degradingthe polymer substantially with respect to its other characteristics.Thus, for example, a reported effort to improve the dyeability ofpolyethylene terephthalate by incorporating within its structure minoramounts of certain amino alcohols, thereby giving the polymer a greaterability to absorb acetate dyes and acid dyes, seriously reduces the heatstability of the polyethylene terephthalate so modified. Another eifortin this direction in volved chemical incorporation of long chainpolyalkylene oxides having molecular weights of the order of 1000 to6000. This modification of the polyethylene terephthalate,unfortunately, made it quite sensitive to air oxidation and to light.Another proposal involved the utilization of toxic carriers such as thechlorobenzenes, chlorophenols, and the like, for the dyeing process.Still another involved the application of vat or acetate dyes undersuperatmospheric pressure at temperatures above 100 C. Another requiredthe use of fiber-swelling agents or dye carriers. Still another involvedthe use of pigments that are mixed directly with the polyethyleneterephthalate melt before spinning.

It is apparent that these efforts have at best had very limited success.The methods involving chemical incorporation of modifying agents such asamino alcohols and polyalkylene oxides have involved substantialreduction in thermal stability, the use of toxic carriers is inherentlyundesirable and dangerous, and special dyeing techniques, such as thoserequiring dyestuffs that are stable at high ice . 2.- inbelow describedare readily dyeable by ordinary dyeing techniques, while at the sametime retaining excellent heat and light stability, dimensional stabilityand other desirable physical properties.

The dyeable linear polyesters of this invention are prepared essentiallyfrom an aromatic dicarboxylic acid or ester-forming derivative thereof,with a diol, such as an acyclic or :alicyclic aliphatic glycol, anaromatic diol, an aliphatic-aromatic diol, or a diester thereof, and asmall amount of a metal]osulfophenoxy-substituted benzoic ormetallosulfobenzoic acid or ester represented by the formula:

I) i i Y I 0 MSOa COOR wherein Y designates a hydrogen atom or ametallosulfo (-SO M) radical; M designates an alkali metal atom, as forinstance, a lithium, sodium, potassium, rubidium or cesium atom, etc.,and preferably designates an alkali metal atom having an atomic numberof from 3 to 19, i.e., a lithium, sodium, or potassium atom; and Rdesignates a hydrogen atom or an alkyl radical preferably containingfrom 1 to about 8 carbon atoms, such as a methyl, ethyl, propyl, bu tyl,hexyl, octyl, or 2-ethylhexyl radical, of

i which the lower alkyl radicals containing from 1 to abouttemperatures, are too expensive to be commercially practicable.

These ditficulties have now been overcome without impairing thecharacteristics of the polyester. Thus, for

wherein M and R are as defined above.

4 carbon atoms are more preferred.

Thus, by way of-further illustration, the metallosulfophenoxybenzoicacids and estersused to prepare dyeable linear polyesters-inaccordancewith this invention can be represented by the sub-generic formula:

MSO; o 0 on wherein M and R are as defined above. As typical of suchcompounds, there can be mentioned:

'2- [4- sodiumsulfo) phenoxy] benzoic acid 2- 3- lithiumsulfo) phenoxy]benzoic acid 2-[2- (potassiumsulfo)phenoxy] benzoic acid3-[4-(sodiunrsulfo)phenoxy] benzoic acid Methyl2-[4-(-s0diumsulfo)phenoxy] benzoate Ethyl 2-[4-(sodiumsulfo)phenoxy]benzoate Similarly, the (metallosulfophenoxy)metallosulfoben zoic acidsand esters used to prepare dyeable linear polyesters in accordance withthis invention can be represented by the subgeneric formula:

(III) OaSM OOOR As typical of such compounds, there can be mentioned:

2- [4- (sodiumsulfo) phenoxy] -5- sodiumsulfo) benzoic acid 2- [3-(lithiumsulfo) phenoxy] -5- (lithiumsulfo) benzoic acid 2-[Z-(pota-ssiumsulfo phenoxy] -5- (potassiumsulfo) benzoic acid 3- [4-sodiumsulfo phe-noxy 1-5- (-sodiurnsulfo) benz oic acid 1 h ,2- [4-(potassiumsulfo) phenoxy] -3- (potassiumsulfo) benzoic acid Methyl 2-[4- sodiumsulfo phenoxy] (sodiumsulfo) benzoate Ethyl 2- 3-(lithiumsulfo phenoxy] -5- (lithiumsulfo benzoate Propyl2-[Z-(potassiumsulfo)phenoxy1-5-(potassiumsulfo)benz'oate 'Butyl 2- [2-(potassiumsulfo phenoxy] -5- (potassiumsulfo) benzoate t HeXyl 3- [4-sodiumsulfo phenoxy] -5- sodiurnsulfo benzoate 2ethylhexyl 3-[4-(sodiumsulfo)phenoxy] -5-(sodiumsulfo) benzoate Octyl 2- [4- (potassiumsulfo phenoxy] -3- (potassiumsulfo) benzoate, and the like.

The metallosulfophenoxy-substituted benzoic and metallo-sulfobenzoicacids and esters contemplated by this invention can be produced by stepswhich include the su'lfonati'on of a member of a known class ofcompounds, viz., the phenoxybenzoic acids and alkyl esters thereofrepresented by the formula:

coon

wherein R is as defined above. As typical of such known 7 compounds,there can be mentioned:

with the followingequation:

OOOR

wherein M designates an alkali metal atom, such as a sodium atom, etc, Xdesignates a halogen atom, such as a chlorine atom, etc., and R is asdefined above. Such a reaction can be carried out by bringing thephenolate' "and the halobenzoic acid or ester into reactive admixtureinaqueous medium at a temperatureof from about 30 C.

to about 100 C., or higher, or, when an ester reactant is employed, inan alcoholic medium under reflux.

The conversion of the phenoxybenzoic acid or ester to the correspondingsulfonic acid derivatives represented by the formula:

' Esos coon V wherein Y designates a hydrogen atom or a sulfo e 4 I('-SO3H) radical, and R is as defined above, can be carried out by knownsulfonation procedures. Thus, for example, the phenoxybenzoic acid orester can be sulfonated by reaction with a mild sulfonating agentcomprised of a mixture of sulfuric acid and acetic anhydride, at atemperature of from about C. to about 50 (1;, and preferably from about0 C. to about 25 C. The

' phenoxybenzoic acid or ester, of which the latter is preferablyemployed, is best introduced to the sulfonating agent in solution using,by way of illustration, an inert solvent, such as methylene dichloride,ethylene dichloride, ethyl acetate or the like. The mole ratio ofsulfuric acid to acetic anhydride in the sulfonating agent can vary fromabout 0.1 to about 1 mole of sulfuric acid per mole of acetic anhydride,with a ratio of from about 0.2 to about 0.6 mole of sulfuric acid permole of acetic anhydride being preferred. .The mole ratio of sulfuricvacid to the phenoxybenzoic acid or ester can vary fromabout 0.5 to.about 5 moles of sulfuric acid per mole of thephenoxybenzoic acid orester, with a ratio of from about 0.8 to

about 1.5' moles of sulfuric acid perrnole of the phenoxybenzoic acid orester being preferred.

The sulfonated productobtained in this manner is ordinarily themonosulfo derivative. When the disulfo derivative is desired, thephenoxybenzoic acid or. ester can be sulfonated by reaction withconcentrated sulfuric acid. At temperatures up to about60 C.,monosulfonation predominates, and yields of up to percent or better ofthe rnonosulfonic acid derivative may be obtained. At temperatures above60 C., and preferably from about C. to about 200 C., disulfonationoccurs to a significant extent. In both instances, however, small yieldsof other sulfonic acid derivatives are also often produced, and varyingthe. temperature employed results in varying the ratio of monosulfo anddisulfo derivatives formed. I

. WhenIe-mploying'concentrated sulfuric acid as the sole sulfonating'agent, the ratio of concentrated sulfuric acid to the phenoxybenzoicacid or ester. can vary from about 1 to about 6 moles of concentratedsulfuric acid per mole of the phenoiiybenzoic acid orester. Lower moleratios within this range favor the formation of the monosulfoderivative, and a ratio of from about 1 to about 3 moles of concentratedsulfuric acid-per mole of the phenoxybenzoic acid or ester is preferredin order to obtain high yields of themonosulfo derivative in thesulfonation reaction. Higher mole ratios favor the formation of thedisulfo derivative, and a ratio of from about 3 to about 5 moles ofconcentrated sulfuricacid per mole of the phenoxybenzoic acid or esteris preferred in order to obtain high yields of thedisulfo derivative inthe sulfonation reaction. Advantageously, a sulfonation catalyst,

"such as mercury, mercuric sulfate, vanadium pentoxide,

or the like, can also be used in the reaction, but its presence is notessential.

Produced as hereinabove described, the sulfonated phenoxybenzoic acid orester can be recovered, if desired, in any convenient manner, such as bycrystallization and filtration, etc. Moreover, While the2-(4-sulfophenoxy) benz-oic acid and 2-(4-sulfo-phenoxy) S-sulfobenZOicacid derivatives are most readily produced, other sulfonated derivativesare also often formed, or can be obtained by varying the sulfonationreaction in a manner determin- The sulfonated p henoxybenzoic acid orester is there- I after reacted with an alkali metal hydroxide oralkoxide',

salt to the sulfonated phenoxybenzoic acid or ester can vary from about1 to about moles of the alkali metalcontaining compound per mole of thesulfonated phenoXybenzoic acid or ester, with a ratio offrom about 1 toabout 3 moles of the alkali metal-containing compound \per mole of thesulfonated phenoxybenzoic acid or ester Being preferred. Moreover, whenthe sulfonated product undergoing reaction is the benzoate ester, theconversion of the product to the alkali metal sulfonate derivative canbe effected conveniently by titration with an alkali metal hydroxide oralkoxide, preferably in alcoholic solution, to a pH of 7 to 8.

The alkali metal sulfonate thus produced can subsequently be recoveredin any convenient manner, such as by filtration, or as the residueproduct obtained upon evaporation of any solvent present, etc., andthereafter employed to prepare dyeable linear polyesters in accordancewith this invention, as hereinbelow described. For convenience, themetallosulfophenoXy-substituted benzoic and metallosulfobenzoic acidsand esters thus produced will herein-after be referred to as themonofunctional dye- .assistant-s of this invention.

Particularly suitable diols for use in preparing the dyeable linearpolyesters of this invention are the acyclic and alicyclic aliphaticglycols containing from 2 to 10 carbon atoms, especially thoserepresented by the general formula HO(CH OH wherein m is an integer offrom 2 to 10, such as ethylene glycol, trimeth-ylene glycol,pentamethylene glycol, hexamethylene glycol, decame thylene glycol, andthe like. Other suitable aliphaticglycols include1,4-cyclohexanedimethanol, 3-ethyl-1, -pentanediol, p-xylylene glycol,and the like. It is known that any glycol of an aliphatic nature,whether or not it contains aromatic nuclei, can be used in theproduction of linear polyesters. Thus, the term aliphatic glycol asemployed herein includes all those glycols of acyclic and alicyclicaliphatic nature which are known to the arttobe suitable. Still other.suitable diols include aliphaticaromatic diols such as 4-hydroxybenzylalcohol, aromatic diols such as hydroquinone, etc. Mixtures of two ormore diols can also be employed, with up to about 10 mole percentorslightly more of any one diol being replaced by a different diol.

Particularly suitable aromatic dicarboxylic acid cornpounds for use inproducing the dyeable linear polyesters of this invention are themonocyclic aromatic dicarboxylic acids and the dialkyl esters thereofpreferably Containing from 1 to about 8 carbon atoms in each alkyl esterradical, especially terephthalic acid and the dialkyl esters thereof,such as dimethyl terephthalate and similar esters in which the alkylester radicals more preferably contain from 1 to about 4 carbon atoms.

aromatic dicarboXylic acids or esters include:

Isophthalic acid,

p,p'-DiphenylcarboXylic acid, p,p'-Dicarboxydiphenyl ethane,p,p-Dicarboxydiphenyl hexane, p,p-Dicarboxydiphenyl sulfide,p,p-Dicarboxydiphenyl sulf one, p,p-Dicarboxydiphenyl ether,p,p-Dicarboxyphenoxy ethane, I I 2,6-naphthalene dicarboxylic acidjtheiralkyl esters; and

the like.

Mixtures of two or more dicarboxylic acids or esters can Other suitablealso be used with up-to about. 10 mol percent or slightly. more-of anyone aromatic clicarboxylic acid or ester being replaced ,by a differentaromatiedicarboxylic acid or ester, or by analiphatic dicarboxylic acidor ester, such as adipic acid, succinic acid, 'sebacic acid, dimethylsebacate, dirnethyl, 1,2-eicosane dioate, dimethyl bicyclo-[2.2.2]-oct-5-ene dicarboxylate, and the like.

Dyeable linear polyesters can also beprepared by the self-condensationof a hydroxycarboxylio acid or hydroxycarboxylic acid ester togetherwitha monofunctional dye-assistant of this invention, or by thepartialreplacement of a 'diol' or aromatic dicarboxylic acid or ester with ahydroxycarboxylic acid or ester-within the limits hereinabove described.

In preparing the dyeable linear polyesters of this invention, at leastabout a 1.3 to 1 molar ratio of diol to dicarboxylic acid or ester isused. However, an excess of diol to the dicarboxylic acid compoundranging fromabout 2 to 10 moles of diol'per mole of the dicarboxylicacid compound can also be used. A more satisfactory ratio is from about1.3 to about 7 moles of diol per mole of the dicarboxylic acid compound,with a ratio of from about 1.5 to about 5 moles of diol per mole of thedicarboxylic acid compound being especially preferred. i

The amount of monofunctional dye-assistant employed in preparing thedyeable linear polyesters of this invention can be varied from about 0.1to about 3.5 mole percent of the dye-assistant based upon the totalamount of dicarboxylic acid compound charged, i.e., as the free acid oras the ester. A preferred ratio isfrom about 0.15 to about 2.5 molepercent of the dye-assistant based upon the total amount of dicarboxylicacid compound charged. While somewhat greater amounts of dyeassistantcan also be employed, the use of a proportion greater than about 5 molepercent of the dye-assistant based upon the total amount of dicarboxylicacid compound charged may have an undesirable eifect upon the molecularweight of the polyester product.

I Moreover, in the formation of a dyeable linear polyester by thereaction of any given dicarboxylic acid or ester with any given diol,especially good results, measurable in termsof improved dyeability, canbe obtained in accordance with this invention when from about 0.1 toabout 5 mole percent of either the dicar boxylic acid compound or thediol is replaced by one or more diflferent comonomers of similardifunctionality. The comonomer can be any of the dicarboxylic acids oresters, diols or hydroxycarboxylic acids or esters hereinabovedescribed, other than the difunctional monomers conventionally employedin preparing a given polyester, as indicated above. The presence of thecomonomer, it is believed, disrupts the crystallinity ofthe polyesterprod net to a limited'extent, thereby making the dye-attractivemetallosulfo radicals of the dye-assistant more accessible to dyemolecules during subsequent dyeing operations. Higher proportions ofcomonomer Within the ranges hereinabove described can also be employed,al though such use is generally attended by little additional advantageinsofar as improved dyeability is concerned.

However, as is known to the art, the comonomer can, by appropriateselection, also serve as a dye-assistant, thereby further enhancing thedyeability of the linear polyesters of this invention. As illustrativeof the difunctional comonomers which can also serve as a dyeassistant,there can be mentioned the mono and di(metallosulfo)fluorenedialkanoicacids and esters, represented by thegeneric formula;

(VII) MSOs Becom ng.) onnmooon with Formula'land It designates aninteger 2- (sodiurnsulfo fiuorene- 9,9.-diacetic acid 7 7 having a valueof from 1 to aboutl-Z, and preferably from 2 to about 8. As typicalthereof, there can be mentioned:

2% (-potassiurnsulfo fluorene-QB-dipropionic acid2-(lithiumsulto)fiuorene-9,9-dihexanoic acid 2,7-di (potassiumsulfofluorene-9-9,-dipropionic acid Dioctyl 2- (sodiumsulfo) fluorene-9,9-diacetate Dibutyl 2- (potassiumsulfo) fluorene-9,9-dipropionate Diethyl 2-(lithiurnsulfo fluorene-9,9-dihexanoate Dimethyl 2 (sediumsulfofluorene-9,9-dioctanoate Dimethyl 2,7 di(potassiumsulfo)fiuorene-9,9dipropionote, and the like. 1

Such compounds can be produced by reactions similar to those describedabove in connectionwith the production of the monofunctionaldye-assistants of this invent tion, employing as the starting material,a 9,9-fluorenedialkanoic acid or ester represented by the formula:

R70 0.0 churn) Q (0.112) 0 0 0 a V tor. When adicarboxylic' acid esteris employed as a reactant, the reaction mixture is heated at atemperature of from about 150 C. to about 270 (3., and preferably fromabout 170 C. to about 260 C., in an inert atmosphere to effect aninitial esterinterchange reaction. Alternatively, an initial directesteritication can be carried out employing the free. dicarboxylicacid'instead of the ester as areactant, Thereafter, any excess glycol isremoved by heating thereaction mixture to a temperature of about 300C.,:underreduced pressure inan inert'atmosphere', or bypassing a streamoi an inert gas through the reaction mixture at atmospheric pressure. Apolycondensation is then carried out by heating the reaction mixture ata temperature of from about 225 C. tov about 325 C., and preferably fromabout 250 C. to about 290 C., under a reducedpressure of from about 0.1mm. to about 20mm. of mercury, and preferably from about 0.1 to aboutmm. of mercury, in an inert'atmos; phere'. If desired, theentirereaction can be carried out at atmospheric pressure while bubblinga streamot inert .gas through the reaction mixture, the rate of gas flowbeingincreased as the polycoridensation proceeds, The total reactionperiod can-be from about one to twelve hours,jaccording to the catalystemployed andits concentration, the temperature, thepressure, thestarting monomers, the viscosity desired for the. polyester product,etc, as isknownto the art. V The monomers are preterably reacted incontact with a suitable catalyst in orderto shorten the reaction periodand thus lessen the possibility of discoloration. Any of the well knownpolyeste ficationcatalysts can be used, such as antimony oxide, incacetate, manganese acetate, cobaltous' acetate, Zinc su'ccinate, Zincborate, magnesium methoxide, sodium methoxide, barium oxide, cadmiumform-ate, litharge, dibutyltin oxide, tetraisopropyl titanate, calciumtitanium silicate, andithe like. Other'conventional catalysts can alsobe employed. The concentration of V the catalyst can be varied fromabout 0.001 to about 1 percentby weight, basedflu'p'on thetot'al amountof dicarero es"? boxylic acid compound cha lustration of the presentinvention.

ged. preferred amount is fromab'out 0.005 to aboutd-S percent by weightof catalyst, and more preterablytrom about 0.01 to about 0.2

ere-cut by Weight of catalyst, based upon the total amount ofdicarboxylic acid compound charged; Other materials can also be includedin the'reaction mixture, as for example, color inhibitors such as alkylor arylphosphites; pigments, delusterants or other additives, such astitanium dioxide or barium carbonate; or viscosity stabilizers, etc.

A typical procedure for preparing the polyesters is described, forexample, in US. 2,465,319, although this pro cedure can be varied by onesk'lled in the art in light of this disclosure. V i

That the monofunctional dye-assistants of this'invention could beemployed in the preparation of high-melting, crystalline, linearpolyesters was surprising and unexpected since phenoxybenzoic a ids andesters, the basic structure or" the dye-assistants, ordinarily discolorand/0r decompose when heated to the temperatures employed in making thepolyesters. Thus, it was unexpected that the dye-assistants would besuificiently stable, both chemically ard procedures, possess medium todeep shades of color having good wash fastness and light fastness, asWell as stability to conventional dry cleaning operations. Fabricsproduced from the fibers are also characterized by a dcsirable hand, andwash-and-Wear properties. The

improved dyeability of the polyesters'is. believed due in no small partto the flexibility or rotatability of the metallosultophenyl radicals ofthemonofunctional dye-assistants of this invention about the adjacentoxygen atom, thereby making the-dye-attractive metallosulfo radicalsmore accessible to dye during dyeing operations. 7

At the same time, the monotunctional dye-assistants advantageously alsoserve aschain-terminators in the polycondensation reaction produciru thepolyesters, thereby aiiording eftectiveand convenient control over themolecular weight of the polyester products. The dye-assistants are, infact, particularly Well suited for use as molecular weight regulators ina continuous polycondensation process due to their extremely lowvolatility. Thus, the compounds are not readily removedfrorn thereaction melt by either vacuum or contact with inert gas which may bepassed through the reaction mixture during the polycondensation.Moreover, since the dye-assistants occur in the resultingpolyesters onlyat the end of linear chains due to their monoiuuction-al structure, theydo not materially affect the desirable physical properties of thepolyesters. Hence, the proportion in which the dye-assistants areemployed or incorporated in accordance with this invention to producepolyesters having improved dyeability, i.e., from about 1 to about 3.5mole percent based upon the total carboxylate content of the polyesters,is ordinarily much less than that in which ditunctional dye-assistants,which interrupt the polymer chain, are conventionally employed. I V

The following specific examples serve as further ili In the examples,the reduced viscosity, (I of the'dyeable linear polyesters of thisinvention was determined by dividing the specific viscosity of asolution of the polyester by the concentration ular, the reducedviscosity of the polyesters was calculated from the equation:

I =FX6 wherein AN is the difference between the flow time of thepolyester solution and the flow time of the solvent,

N is the flow time of the solvent, and C is the concentration of thepolymer in grams per 100 milliliters of solution. The reducedviscosities were obtained 'at a polymer concentration of 0.2 gram per100 milliliters of solution, using a 3:2 mixture of phenol andtetrachloroethane as the solvent. The reduced viscosity of thepolyesters can vary from about 0.2 to about 3, with values from about0.35 to about 1 being preferred.

The dyeable linear polyesters of this invention were melt-spun to formfilaments and yarns. Before meltspinning, the polyesters weredriedovernight at a temperature of 90 C. under a reduced pressure of 2 mm.

mercury, and then melt-extruded in a plunger-type spinning machine at atemperature of from 270 C. to 295 C. using a spinnerette having 30holes, each 0.015 inch in diameter. The orifice velocity was 3 feet perminute and the yarn was taken up at 150 feet per minute, a draw ratio of50:1. The yarn was hot-stretched at a temperature of 90 C. around anelectrically heated pin to an extent of from 200 to 500 percent, andthen continuously annealed at a temperature of 150 C. over anelectrically'heated bar, allowing 10 percent relaxation. The yarn wasthen woven into fabrics and dyed. The spinning procedure used isconventional for polyesters, and iswell known to the art. V i I The.fabrics were dyed by standard procedures in the absence of, and usingdye-carriers. The dye baths used had a liquor-to-fiber bath ratio of40:1 and, based upon the weight of the fabric to be dyed, contained 1percent by weight of nonyl phenyl polyethylene glycol ether in the caseof a basic dyebath, and l percent by weight of sodiumN-methyl-N-oleoyltaurate in the case of a disperse dyebath. The dyeconcentration was 3 percent by weight based on the weight of the fabric.

In a typical dyeing procedure, the various components of the dyebathwere admixed and made up to volume with distilled water. paste in 0.25percent by weight of acetic acid, based upon the weight of the fabric tobe dyed. The fabric was scoured in a commercially availablewasher anddried in a commercially'available drier. About 5 to grams of the fabricwas added to the dyebath, and theftemalkyl phenyl'polyethylene glycolether surfactant and 0.25 percent by weight of soda ash, based upon theweight of the fabric, at a temperature of 60 C. for a period of minutes.The dyed and scoured fabric was finally rinsed in-- water and air dried.

Among the basic and disperse dyestuffs which readily The dyestufl wasintroducedras a 10 Rhodamine B (Basic Violet l0, Color Index No. 45170);Sevron Yellow R (Basic Yellow 11, Color Index No. 48055); Celliton FastPink BA (Disperse Red 15, Color Index No. 60710); Latyl Blue FL; MaxilonRed BL; Sevron Brilliant Red 4G (Basic Red 14); Sevron Blue 5G (BasicBlue 4, Color Index No. 51004); and the like.

' EXAMPLE I A mixture of 170 grams of dimethyl terephthalate, 7.093grams of methyl 2-[4-(sodiumsulfo)phenoxy]- benzoate, 170 grams ofethylene glycol, 0.053 gram of antimony oxide and 0.079 gram of zincacetate was charged to a reactor and heated at a temperature of 180 C.for a period of 4.75 hours to bring about an ester exchange, whiledistilling the methanol formed during the reaction. The reaction mixturewas then heated at a temperature of 270 C. for a period of 1- hour toremove the glycol excess. Thereafter, the temperature of the reactionmixture was maintained at 270 C. for a period of 5 hours to carry out apolycondensation.

' During the reaction, a vigorous stream of nitrogen was dye-assistantof this invention.

passed through the reaction mixture at atmospheric pressure. A white,crystalline polyester was thereby obtained,

having a reduced viscosity of 0.47 and a melting point 7 were dyed toonly a verylight shade with Celliton Fast Red GGA Ex. Conc.

EXAMPLE II A mixture of 170 grams of dimethyl terephthalate, 4.72 gramsof methyl 2-[4-(sodiumsulfo)phenoxy]benzoate, 170 grams of ethyleneglycol, 0.052 gram of antimony oxide and 0.070 gram of zinc acetate wascharged to a reactor and heated at a temperature of l80 C. for a periodof 4.75 hours to bring about an ester exchange, .While distilling themethanol formed during the reaction.

The reaction mixture was then heated at a temperature of 2 C. for aperiod of 1.25 hours to remove the glycol'excess. Thereafter, thetemperature of the reaction mixture was maintained between 270 C. and260 C. for a period of 5.5 hours to carry out a polycondensation. Duringthe reaction, avigorous stream of nitrogen was passed through thereaction mixture at atmospheric pressure. A white, crystalline polyesterwas thus obtained, having a reduced viscosity of 0.48 and a meltingpoint of 256258 C. The polyester had excellent dye the fibers producedfrorn the polyesters of this invention one can mention the Genacryl dyesdiscussed on pages 432 to 433 of the American Dyestuif Reporter, Volume43, 1954, for example, Genacryl Red 6B (Basic Violet 7, Color Index No.48020); Genacryl Pink G (Basic Red 13, Color Index No. 48015); GenacrylBlue 6G (Basic Blue 1, ColorIndex No. 42025); Celliton- Fast Red GGA Ex.Conc. (Disperse'Red 17, Color. In-

' dex No. 11210); Celliton Fast Blue AF 'Ex. Conc. (Dis dyeable fiberforming and cold-drawing properties. Fibers, melt-spun from thispolyester were dyed to a medium shade with Genacryl Pink G and to' abright shade. with Celliton Fast Red GGA Ex. Conc. without the use of acarrier. Similarly dyeable fibers are also obtained from the polyesterprepared as described above in this example, employing methyl2-[3-(lithiumsulfo) phenoxy1benzoate as the monofunctional dye-assistantof this invention. EXAMPLE III A mixture of grams of dimethylterephthalate, 5.56

grams of methyl 2-. [4 (sodiumsulfo) phenoxy] benzoate, 120 grams ofethylene glycol,i0.053 gram of antimony oxide and 0.079 gram of zincacetate was charged to a reactor and heated at a temperature of C. for aperiod of 5.5 hours to. bring about an ester exchange, while distillingthe methanol formed during the reaction.

line polyester was thus obtained, having a reduced viscosity of 0.48 anda melting point of 256-258 C. The polyesterwas characterized byexcellent dyeable fiberformingand cold-drawing properties. Fibersmelt-spun from this polyester were dyed to a medium shade with MaxilonRed BL without the use of a carrier. Similarly dyeable fibers are alsoobtained from the polyest'er prepared as described above in thisexample, employing methyl 2-[4-(potassiumsulfo)phenoxy]benzoate as themonofunctional dye-assistant of thisinvention. By way;

of comparison, fibers melt-spun from a polyethyleneterephthalatepolyester, i.e., excluding the monofunctional dye-assistant of thisinvention, were not dyed by Maxilon Red BL. 5'

' 7 EXAMPLE 1v A mixture or" 170 grams of dimethyl terephthala te, 3.71

grams of methyl 2-[4-(sodiumsulfo)phenoxy]benzoate, 120 grams ofethylene glycol, 0.017 :gram of antimony oxide and 0.078 gram of zincacetate was charged to a The reaction mixture was then heated at atemperature 12 EIQKMPLE VI A mixture of 197.53 grams of dimethyl'terephthalate,

6.6 grams of methyl 2-[4-(sodiumsulfo)phenoxylbenzoate,'4.532 gramsofdimethyl 2- (sodiumsulfo)fiuorene- 9,9-dipropionate, 140 grams ofethylene glycol, 0.063

gram of antimony oxide and, 0.094 gram of zinc acetate was charged to areactor and heated at a temperature of 180 C. for a period of 4.5hoursto bring about an ester exchange, while distilling the methanol formedduring the reaction. The reaction mixture was then heated at atemperature of 265- C. for a period of 1.25 hours to remove the glycolexcess. Thereafter, the temperature of the reaction mixture wasmaintained at 265 C. for a period of 6 hours to carryout apolycondensation. 'During the reaction, a vigorous stream of nitrogenwas passed through the reaction mixture at atmospheric pressure. Awhite, crystalline polyester was thus obtained, having a reducedviscosity of 0.45 and a melting point of 256- 258 C. The polyester wascharacterized; by excellent reactor and heated at a temperature sr1ss C.for a period of 3.25 hours to'bring about an ester exchange, whiledistilling the methanol formed during the reaction;

The reaction mixture was then heated at a temperature of 270 C. foraperiod of 2.5 hours to remove the glycol excess. Thereafter, thetemperature of the reactionmix- 'ture was maintained at 270 C. at apressure of 2' mm. of mercury for a period of 5 hours to carryioutapolycondensation. During the reaction, a stream-of nitrogen waspassed-through the reaction mixture. A white, crysfGGA Cone. withouttheuse of a carrier; Fibers'of improved dye'ability are also obtained fromthe polyesters prepared as'described above in this example, replacing'ap'proxirnately'5 mole percentof the dimethyl terephthalatej reactantwith dimethyl isophthalat'e.

V QEXAMPLEQVV A mixtureof 2 08. 59 grams ot-'diinethyl terephthalate,

dyeable fiber-forrningand cold-drawing properties. Fibers melt-spun fromthis polyesterwe're dyed to a very deep shade with MaxilonRed BLwithout'th'e use of a carrier. Similarly dyeable fibers are alsoobtained from the polyester'prepared as described above in this example,replacingthe ethylene glycol reactant with an equimolar amount ofl,4-cyclohexanedimethanol.

EXAMPLE VII zoate, 4.7- grams of dimethyl 2('sodiur'nsulfo)fluorene-9,9-

dipropionate, 120 grams of ethyleneglyc'jol, 0.019 gram offantimonyoxide and 0. 084 gram of zinc acetate was charged to a reactor andheatedat a temperature of 185 C. for a period of 3.25 hours to bringabout an ester exchange, while. distilling the methanol-formed duringthe reaction.- The reaction mixture-was then heated at talline polyesterwas thus obtained, having a reduced move the glycol excess.

a temperature of 260 C. for a period of 2.5 hours to re- Thereafter, thetemperature of the reaction'nrixturew'as maintained at 260 C. at'apressure of 3 mm. of mercury for a periodof 5.75 hours to carryout apolycondensation'. During'the reaction, a stream of nitrogen waspassedthroug'h the reaction mix- "fturef A'white, crystallinepolyesterwas thuslob tained,

having a reduced 'viscosity of 0.44 and a melting point of 236239 C. Thepolyester was characterized by excel- 5.894 grams'ofmethyl 2-[l-(sodiurnsulfo)phenoxy]benzoate, 3 .5 73' grams 1 of dimethyl 2-(sodiumsulfo)fiuorenei 9,9-dipropionate, 200 grams of ethylene glycol,0.0654

gram of antimony oxide and 0.0981 gram of zinc acetate was charged to areactor and heated at a temperature of 180 C; for aperiodof 4.25hours tobring about an ester exchange, "while distilling the methanol formedduring the reaction.

The reaction mixture wasthenheated at a temperature of 260 C; for aperiod of 1.5'l1ours to remove the glycol excess. Thereafter,thetemperature of the reaction mixture was maintained at 260 C. .for'aperiodv of 6 hours to carry out a polycondensation. gDuring thereaction, a vigorous stream of nitrogen was passed through the reactionmixture at'atmcspheric' pressure.

A white,- crystalline. polyester was thus obtained, having a re'duc'edviscosity oi'0.44 and a meltiug point of 256- 258C. 'The'polyester wascharacterized by excellent 'dy'eable fiber-forming and cold-drawingproperties. Fiber-s V nielt s'pu'n from thispolyester' werefdyedto avery deep shade with .Gena-cryl PinleG and'with. Celliton Fast Red GGAExL Conc, withoutlthe use of 'a carrier. This ex- "ample' illustratesdheuse of'a difunctional comonorner Y which is also ady'e-assistant.

lent dyeable fibenfor'ming-and cold-drawing properties.

:Fibers melt-spun from this polyester were dyed to a very deep shadewith Maxilon RedBLandwith'Celliton Fast about an ester exchange,whiledistilling the methanol formed during the reaction, :The reaction.mixture was then heated'at a temperature of; from 220 C. to 265 C.. foraperiod of 4.25 hours toremove the glycol excess. Thereafter, thetemperature of the reaction mixture was maintained in the range of from269C. to 271C. for a period of 2.75 hours to carry out apolyconidensation. During the reaction, a vigorous stream of nitrogenwas "passed through the'reaction mixture at atmospheric pressure. Awhite-crystalline; polyester was thus obtained,

having a'reduced'viscosity 0150.47 and a meltingpoint of 245248 C. Thepolyester wascharacte'rized by excellent "dyeable' fiber-torming 'andcold-drawing properties.

Fibers melt-spun from this polyester were' dyed to a medium shade withboth Genacryl Pink G and Celliton Fast Red GGA Ex. Cone. without the useof a carrier.

The following experiments illustratethe preparation of several of themonofunctional dye-assistants of this invention. Similar procedures canbe used to'produce the To a 500 milliliter 4-necked flask equipped witha stirrer, condenser, thermometer, and dropping funnel, there wascharged 102 grams of acetic anhydride. The anhydride was cooled to atemperature of 10 C., whereupon 54 grams of sulfuric acid were addeddropwise thereto, accompanied by stirring and continued cooling, so thatthe temperature of the resulting mixture was maintained at about C. Tothis mixture, there were slowly added 114 grams of methylZ-phenoxybenzoate. The addition was effected over a period of 30minutes,

1 accompanied and followed by continued stirring and cooling, so thatthe temperature of the resulting mixture was maintained ini the range,of from 0 C. to C. for a In this manner, a solution of methyl2-(4-sulfophenoxy)- benzoate was obtained. To thisLsolution, .there wereadded 250 milliliters .of methanol. The resulting solution then wasrefluxed for a period of 6 hoursto esterify the acid present, whichincluded the acetic anhydride component of the sulfonating agent. Themethyl acetate formed during estenification was removed as a distillateduring the reflux period, and replaced with fresh methanol to maintain aconstant volume of about 400 milliliters. The solution was then cooledto about room temperature and titrated with a methanolic sodiumhydroxide solution of a pH of 7.2. A precipitate was formedand wasfiltered and purified by recrystallization once from .dioxane and oncefrom methanol. In this manner, 66, grams of substantially pure methyl2-. [4-(sodiumsulfo)phenoxy] benzoate were obtained. Analysis.Calculatedtor C H O SNa: C, 50.91; H, 3.36. Found: C, 50.69; H, 3.49. Infraredanalysis was consistent therewith. In like manner, butyl2-'[4-(potassiumsu1fo)phenoxy]benzoate is produced by the sulfonation of2-phenoxybenzoic acid, followed by esterification with butanol and thentitration with potassium hydroxide.

What is claimed. is; V

1. A dyeable linear polyester consisting essentially of the condensationproduct of (a) 'a dicarboxylic acid compound selected from the groupconsisting of the monocyclic aromatic dicarboxylic acids and the dialkylesters thereof; (b) an aliphatic glycol containing from 2 to 10 carbonatoms; and, based upon the total amount of said dicarboxylic acidcompound, (0) from about 0.1 to about 3.5 mole percent of a compound ofthe formula:

MSO; coon wherein M is an alkali metal and R is selected from the groupconsisting of hydrogen and alkyl.

2. A dyeable linear polyester consisting essentially of the condensationproduct of (a) dimethyl terephthalate; (b) a compound of the formula:

M80 COOR wherein M is an alkali metal having an atomic number of from 3to 19, and is methyl.

3. A dyeable linear polyester consisting essentially o the condensationproduct of (a) dimethyl terephthalate;

(b) ethylene glycol; and, based upon the total amount of said dimethylterephthalate, (c) from about 0.1 to'about V 3.5 mole percent of acompoundof the 'formula:

COOR

wherein M is an alkali metal having an atomic number of from 3 to 19,and R is methyl.

4. A dyeable linear polyester consisting essentially of the condensationproduct of (a) dimethyl terephthalate; (b) ethyleneglycol; and, basedupon the total amount 'of said dimethyl terephthalate, (c) from about0.15 to about 2.5 mole percent of methyl 2-[4-sodiumsulfo)phenoxy]benzoatei 5. A dyeable linear polyester consisting essentially of thecondensation product of (a):din1ethyl terephthalate; (b) ethyleneglycol; and, based upon the total amount of said dimethyl terephthalate,(c) from about 0.15 to about 2.5 mole percent of methyl2-[4-(potassiumsulfo) phenoxy]benzoate.

6. A dyeable linearpolyester consisting essentially of the condensationproduct of (a) dimethyl terephthalate; (b) 1,4-cyclohexanedimethanol;and, based upon the total amount of said dimethyl terephthalate, (c)from about 0.1 to about.3.5 mole percent of a compound of the formula:

Msoa COOR O Msoag @000 wherein M is an alkali metal having an atomicnumber of from 3 to 19, and R is methyl.

said mixture of dicarboxylic acid compounds, (c) from about 0.15 toabout 2.5 mole percent of methyl 2- [4-(sodit '8. A dyeable linearpolyester consisting of (a) a mixture of dicarboxylic acid compoundsconsisting of from about to about 99.9 mole percent of dimethylterephthalate and from about 0.1 to about 10 mole percent of dimethyl 2(potassiumsulfo)-fluorene-9,9-dipropionate; (b) ethylene glycol; and,based upon the total amount of said mixture of dicarboxylic acidcompounds, (0) from about 0.15 to about 2.5 mole percent of a compoundof the formula:

wherein M is an alkali metal having an atomic number of from 3 to 19,and R is methyl.

9. A dyeable linear polyester consisting of (a) a mixture ofdicarboxylic acid compounds consisting of from about 90 to about 99.9mole percent of dimethyl terephthalate and from about 0.1 to about 10mole percent of dimethyl 2 (potassiumsulfo)-fluoreue-9,9-dipropionate;(b) ethylene glycol; and, based upon the total amount ofumsulfo)phenoxy1benzoate.

10. A heat-stretched, dyeable textile article composed of a dyeablelinear polyester consisting essentially of the Y l condensation productof (a) afdicar'boxylic pound selected from the :g'roup consisting of themonocyclic aromatic. dicarboxylic acids and the dialkyl esters 7thereof; (b) an aliphatic glycol containing from'2 to 10 carbon atoms;.and, based upon the total amount of said dicarboxylic acid compound,(0) from about 0.1 to about 3.5 mole percent of a compound of theformula:

wherein M' is an alkali metal and R is selected from the 7 groupconsisting of hydrogen and alkyl.

11. Aheat-stretched, 'd-yeable textile article composed of a dyeablelinear polyester consisting essentially of the condensation product of.(a) dimethyl terephthalate;

(b) a compound of the 'formula:

irowuom u wherein m'is an integer of from 2 to 10; and, based upon 7acid comamount of said dimethylterephthalate, (c) 'f rom'about 0.1 to.about 3.5 mole percent ofa compound of the a formula:

the total amount of said dimethyl terephthalate, (c) from about 0.1 toabout 3.5 molepercent of a compound of the formula: V i

wherein M is an alkali metal having an atomicnumber of from 3 to 19, andR is methyl. r

12. A heat-stretched, dyeable textile article composed of a dyeablelinear;polye'ster consistingessentially of'the condensation product of(a) dimethyl terephthalate; ('b) ethylene glycol;and based uponthe totalamount ofwsaid dimethylterephthalate; (a) from about 0.1 to about 3.5mole percent'of a compound of the formula:

Mso; coon wherein M is an alkali metal having an atomic number of from 3to 19, and R is methyl.

13. A heat-stretched, dyeable textile article composed I of a dyeablelinear polyester consisting essentially of the condensation product of(a) dimethyl terephthalate;

. .(b) ethylene glycolyandibased upon the total amount of saiddimethylterephthalate, (c) from-about 0.15 to about 2.5 mole percent of methylI2-[4(sodium'sulfo)- phendxyJbenZoate. i

14. A'heat-stretched,"dyeableztextile article composed ofa dyeablelinear-polyester. consisting essentially of the condensation product of(a) 'dimethyl terephthalate;

(b) ethylene glycol; and, based upon the total amount of said dimethylterephthalate, ('c) from about 0.15 to about 2.5 mole percent of methyl2-[4-(potassiumsulfo)pl1enoxy] beuzoate.

15. A heat-stretched, dyeable textile article composed of a dyeablelinear polyester consisting essentially Of the condensation product of(a) dimethyl terephthalate;

(b) 1,4-cyclohexanedimethanol; and, based uponthe-total of from 3 to 19,and His methyl;v I

sog coon wherein M is an alkali metal'having an atomic number of from 3to 19, and R is methyl.

17. A heat-stretched, dyeable textile article. composed of a dyeablelinear polyester consisting of (a) a mixture of dicarboxylic-'acid,co'mpounds consisting of from about to about 99.9 mole percent ofdimethyl terephthalate and from about 0.1 to about 10 mole percent ofdimethyl Z-(potassiumsulfo)fluorene-9,9-dipropionate; (b) ethyleneglycol; and, based .upon the total amount of said mixture ofdicarboxylic acid compounds, (0) from about 0.15 to about 2.5 molepercent'of a compound of the formula:

wherein M is an alkali metal having an atomic number 18. Aheat-stretched, dyeable textile article composed of a 'd'yeable linearpolyester consisting of (a) a mixture of dicarboxylic acid compoundsconsisting of from about 90 to about 99 .9 mole percent of dimethylterephthalate and from about 0.1 to about 10 mole percent of dimethyl2-(potassiumsulfo)fluorene-9,9-dipr0pionate; (b) ethylene glycol; and,based upon the total amount of said mixture'of dicarboxylicacid'compounds, (0) from about 0.15 to about 2.5 mole percent of methyl2-[4-(sodiumsulfo)phenoxy]benzoate.

Reterenees Cited in the file of this patent V UNITED STATESTPATENTS2,901,466

Kibler et al. Aug. 25, 1959 2,970,165 Michel et a1. Ian. 31, 19613,018,272 Griffing et al Ian. 23, 1962 FOREIGN PATENTS 549,179

Belgium l un, Oct. 15, 1956

1. A DYEABLE LINEAR POLYESTER CONSISTING ESSENTIALLY OF THE CONDENSATION PRODUCT OF (A) A DICARBOXYLIC ACID COMPOUND SELECTED FROM THE GROUP CONSISTING OF THE MONOCYCLIC AROMATIC DICARBOXYLIC ACIDS AND THE DIALKYL ESTERS THEREOF; (B) AN ALIPHATIC GLYCOL CONTAINING FROM 2 TO 10 CARBON ATOMS; AND, BASED UPON THE TOTAL AMOUNT OF SAID DICARBOXYLIC ACID COMPOUND, (C) FROM ABOUT 0.1 TO ABOUT 3.5 MOLE PERCENT OF A COMPOUND OF THE FORMULA: 